Note first that knowledge of one's own thought-contents would not count as a priori according to the usual criteria for knowledge of this kind. Surely, then, incompatibilists are using this term to refer to some other, stipulatively defined, epistemic property. But could this be, as suggested by McKinsey { 1 99 1: 9), the property of being knowable 'just by thinking' or 'from the armchair'? Certainly not if these were metaphors for knowledge attainable on the basis of reason alone, since self-knowledge would fail to come out a priori in this sense. And exactly the same would happen if the property were that of being knowable by inference, since, according to a common intuition, self-knowledge is noninferential